Engine Warning Light Ambiguity - Alfa Romeo Forum
You are currently unregistered, register for more features.    
Reply
 
Thread Tools
(Post Link) post #1 of 32 Old 13-01-08 Thread Starter
Status: -
AO Member
 
Jsutton's Avatar
 
Join Date: May 2005
Location: Pembrokeshire
Posts: 265

Member car:

Alfa Romeo 147

Engine Warning Light Ambiguity

Hey
I have had the engine management light repeatedly showing up on my dashboard. I have taken it to a relatively nearby Fiat garage (there is no Alfa Romeo garage within a 60 mile radius of me) and the rather rude mechanic basically just reset the system and printed out a series of error codes. The error code was pertaining an additive or something. I have the error codes here if anyone can give me a better idea from quoting them (i think there was three in total). The engine management light stayed off for about 2 weeks, it then returned and has since turned itself back off. I have noticed no decline in engine performance, except maybe a decrease in fuel efficiency. It has turned on and switched itself off about 4 times now. What do you think it could be? Has anyone here had any experiance with this problem?
Thanks
J.Sutton
Jsutton is offline  
Sponsored Links
Advertisement
 
Status: SOLD my 156!
AO Gold Member
 
gazza82's Avatar
 
Join Date: Jan 2003
Location: United Kingdom
County: Buckinghamshire
Posts: 9,094
Re: Engine Warning Light Ambiguity

Post the codes you have .... it will help us
gazza82 is offline  
(Post Link) post #3 of 32 Old 16-01-08 Thread Starter
Status: -
AO Member
 
Jsutton's Avatar
 
Join Date: May 2005
Location: Pembrokeshire
Posts: 265

Member car:

Alfa Romeo 147

Help Re: Engine Warning Light Ambiguity

Hey guys
The light has reappeared on my dashboard today. I rang my nearest Alfa garage and gave them the codes I have printed out from the diagnostic computer. They told me that these sort of problems can range in severity from lambda probes to ECU systems and that it can get rather expensive . Why can't someone just give me a less ambiguous cause to this problem? These engine management codes aren't exactly precise are they...
Anyway, I am hoping that someone else on this forum has experienced a similar problem? Does anyone know what its sporadic appearances may indicate? Here are the error codes quoted by the Examiner Smart HD:
P1177- Mixture 1 strength (multiplicative) Intermittent
P1178- Mixture 2 strength (multiplicative) Intermittent
P1173- Mixture 1 strength (additive) Intermittent

I am rather perplexed by this problem. I'm hoping that one of you guys may be able to shed some light on the culprit?

Thanks
J.Sutton
Jsutton is offline  
Status: -
AO Member
 
Mr T's Avatar
 
Join Date: Dec 2001
Location: Up North
Posts: 993

Member car:

GTV Cup, GT

Re: Engine Warning Light Ambiguity

I've seen the same type of problem before. The fault codes are telling you that the fuel mixture is falling outwidth the EOBD parameters.

Does the engine management light tend to come on while your sitting in traffic?

Also have you ever noticed a hestiation when accelerating? I noticed it everytime I reset the management light for about 20 miles or so.

Basicly I think there is two likely faults, a lambda probe or Mass AirFlow sensor. Everytime in the past with me it's been the MAF sensor.

The reason that they are not appearing as faults, is they have not fallen outwidth there fault parameters, but are causing the fuel mixture to fall outwidth the EOBD parameters, think this may be due to the long term fuel trim.

The only way to find out is to run a diagnostic on the car as it runs. To find out if the lambda voltages are switching correctly or the MAF sensor is hitting the right range. I think this requires someone with experience, not cheap or replacing the MAF, then the lambda if it doesn't cure the fault. I seriously doubt the ECU will be at fault, but then you never know.

I can try and see if I can find the idle voltage for the MAF, you'll just need to probe it with a multimeter. You can also do the same with the lambda to make sure it's switching.

Sorry it aint clear, hope this helps.

Last edited by Mr T; 16-01-08 at 16:59. Reason: spelling
Mr T is offline  
(Post Link) post #5 of 32 Old 17-01-08 Thread Starter
Status: -
AO Member
 
Jsutton's Avatar
 
Join Date: May 2005
Location: Pembrokeshire
Posts: 265

Member car:

Alfa Romeo 147

Re: Engine Warning Light Ambiguity

Hiya Mr T
Thanks for the reply. I was beginning to think there was no one out there that had experienced such a problem. So you say that you have also experienced this fault? I can't say I’ve noticed any decline in acceleration but my trip computer is reading a terrible consumption average of 25mpg! I do a lot of town driving, but that really is low isn't it... I was getting around 30mpg before.
If it is possible I would like to be able to test the MAF or Lambda myself, but don't even know where to look...
Can self diagnosis be achieved by a relative amateur? At least then I could point the garage in the right direction as I do find that they lead one up the garden path these days. I’ve been to at least 3 different garages and not one of them has been able to tell me what’s wrong.
So can I ascertain whether the Lambda of MAF is faulty myself?

Thanks
J.Sutton
Jsutton is offline  
Status: SOLD my 156!
AO Gold Member
 
gazza82's Avatar
 
Join Date: Jan 2003
Location: United Kingdom
County: Buckinghamshire
Posts: 9,094
Re: Engine Warning Light Ambiguity

I get Trim errors on my TS which I am convinced is the Lambda (NTK part) as I replaced the MAF a few weeks back and got them before and after. Short of replacing the lambda with a new one (use Bosch not NTK ... different ohm ratings) I'm not 100% sure how to test it other than through a diagnostic (I use AlfaDiag as I have a pre-EOBD car). The lambda should switch between +ve and -ve voltages when it is running ... there are 4 wires and two are for the heating element in the lambda sensor. This might help Lambda Sensors or NTK tests

cheers, Gary

HIS: ex-1998 156 2.0 TSpark with Sport Pack 2, sunroof and hi-level spoiler in Alfa Rosso. V6 intake mod, clear side repeaters and Zeatek undertray. 10th Sep 1998 to 12th Jan 2017

HERS: 2009 MiTo 1.4 95bhp Turismo arrived 21st November in Techno Grey with colour-coded headlight surrounds.

My Alfa156 Web Site - how-to's, piccies, links, useful stuff, etc.
gazza82 is offline  
jug
Status: -
AO Silver Member
 
jug's Avatar
 
Join Date: Jul 2007
Location: United Kingdom
County: Durham
Posts: 3,681
Re: Engine Warning Light Ambiguity

funnily enough i've seen the exact same thing from a lazy lambda on a few cars.
jug is offline  
(Post Link) post #8 of 32 Old 29-01-08 Thread Starter
Status: -
AO Member
 
Jsutton's Avatar
 
Join Date: May 2005
Location: Pembrokeshire
Posts: 265

Member car:

Alfa Romeo 147

Re: Engine Warning Light Ambiguity

I've just been to an Alfa garage and they have informed me that it's in fact due to two faulty lambda probes. They could not fit them the same day however, and i have a long way to travel in order to get to them. They also quoted me a price of about 302 to have them fitted.
I am thinking of buying the lambda probes myself and paying a local garage to carry out the work. Where is the best place to try for lambda probes to fit a 1.6 TS 147 (120bhp)?
How difficult is it to install these lambda probes?

Thanks
J.Sutton
Jsutton is offline  
jug
Status: -
AO Silver Member
 
jug's Avatar
 
Join Date: Jul 2007
Location: United Kingdom
County: Durham
Posts: 3,681
Re: Engine Warning Light Ambiguity

if you want universal lambdas then your local motorfactor can supply them cheaply (£40 each usually), and you can easily fit them yourself all you need to do is join a few wires.
jug is offline  
Status: -
AO Member
 
charlie8's Avatar
 
Join Date: Jun 2005
Posts: 106

Member car:

GT JTS 2.0

Re: Engine Warning Light Ambiguity

This thread seems to have drilled down to some detail concerning the MCSF light, so hopefully someone can answer this.

Once a fault occurs, am I right in that the dash message will show for the duration of the fault in real-time and the yellow light will show as long a fault code is stored. In my case when off, the err only shows when 5/6 miles into a journey, 5 secs for message and yellow on for a few days then goes off. So if 1 have 1 reading in 50 million over 3 days, the code stores but then clears itself ? When yellow is on the message comes up from start for that 5 secs again, but thats it.

My thinking is that the lamba is ( for an instance ) picking up to rich for a very short time as the temp comes up to normal temp. Then its fine. I monitored my 'actual' consumption from cold and it starts 8-10mpg while its cold, but ofter a few miles goes up to 27 mpg which is what I always had, no clearly not a problem once to temp.

As this code means zillions of things, just trying to narrow mine given someone here seems to know the spec of the ECU err handling ?

C

Quote:
There's nothing in the dark that isn't there in the light ..... except fear
charlie8 is offline  
Dibby
Status: - Update
Guest
 
Posts: n/a
Re: Engine Warning Light Ambiguity

Quote:
Originally Posted by charlie8 View Post
Once a fault occurs, am I right in that the dash message will show for the duration of the fault in real-time and the yellow light will show as long a fault code is stored. In my case when off, the err only shows when 5/6 miles into a journey, 5 secs for message and yellow on for a few days then goes off. So if 1 have 1 reading in 50 million over 3 days, the code stores but then clears itself ? When yellow is on the message comes up from start for that 5 secs again, but thats it.
Not entirely, the light comes on when the error is present but if the error clears itself and the car's tests on startup come back clean, the light will go off but the code will be stored in the memory. The car cannot wipe its own memory, if it finds a fault it will be stored and even if the light if off you can get the codes read out of it to trace the problem.

After a MCSF, mine takes 5 restarts to get rid of the yellow light but the codes are all there in the car's memory for ever until they're cleared by a garage.
 
jug
Status: -
AO Silver Member
 
jug's Avatar
 
Join Date: Jul 2007
Location: United Kingdom
County: Durham
Posts: 3,681
Re: Engine Warning Light Ambiguity

Quote:
Originally Posted by charlie8 View Post
Once a fault occurs, am I right in that the dash message will show for the duration of the fault in real-time and the yellow light will show as long a fault code is stored.
no, light on means fault currently occuring. once the fault is fixed the light goes off but the fault code remains in ecu until it is cleared.
jug is offline  
Status: -
AO Member
 
charlie8's Avatar
 
Join Date: Jun 2005
Posts: 106

Member car:

GT JTS 2.0

Re: Engine Warning Light Ambiguity

Hmm, this cannot be true.

If the garage clears the code, the light goes out with no cure on next startup
charlie8 is offline  
Dibby
Status: - Update
Guest
 
Posts: n/a
Re: Engine Warning Light Ambiguity

If the garage clears the code the light will go out. If the fault reappears the light will come back on again.
 
Status: -
AO Member
 
charlie8's Avatar
 
Join Date: Jun 2005
Posts: 106

Member car:

GT JTS 2.0

Re: Engine Warning Light Ambiguity

Yes, but it can be on for 2 weeks, cleared by garage and off for 3 days with no fix, so it cannot be only on while the fault occurs else it would come straight back on when cleared. I think there must be a time delay against the stored code.
charlie8 is offline  
Dibby
Status: - Update
Guest
 
Posts: n/a
Re: Engine Warning Light Ambiguity

Is it an intermittent fault? When you turn the car on after the reset, everything could be reporting back to the ECU fine and the error only shows itself again when something gets too hot/ too cold/ too much pressure/ a connection is lost.

Mine can be fine for a month or so before it trips out and then the light's on for a week.
 
jug
Status: -
AO Silver Member
 
jug's Avatar
 
Join Date: Jul 2007
Location: United Kingdom
County: Durham
Posts: 3,681
Re: Engine Warning Light Ambiguity

Quote:
Originally Posted by charlie8 View Post
Yes, but it can be on for 2 weeks, cleared by garage and off for 3 days with no fix, so it cannot be only on while the fault occurs else it would come straight back on when cleared. I think there must be a time delay against the stored code.
for some types of fault the light will only go off after a number of successful "drive cycles", and similarly only switch on after a number of unseccessful drive cycles. depending on how you use the car that could take 1 day or a few weeks to happen. dealers know this, they use it to their advantage, clearing fault codes instead of fixing the fault, then when you go back a few days later they recharge you.

a light that come and goes if often due to the lambda, an easy way to check is to add redex to your fuel, but in a stonger mix than the bottle suggests (i use 2 bottles in quarter of a tank) if that switches the light off within 50miles then you can be fairly certain your problem is a lambda sensor going out of range, often because unburnt fuel it hitting it.
jug is offline  
Status: -
AO Member
 
charlie8's Avatar
 
Join Date: Jun 2005
Posts: 106

Member car:

GT JTS 2.0

Re: Engine Warning Light Ambiguity

Ok, good stuff, thanks guys. So here is my scenario ( with no driveabilty issues ever )

Dash message, light on - panic, garage find lamba faults but cannot see when sensor tested in isolation. So just reset codes
2 weeks
Dash message, light on - Given understand it a bit more not so worried to carry on driving at low RPM
2 weeks
Garage reset and find fault using R/T diagnostic on 1 out of many trips and replace a lambda
3 days
Dash message, light on
2 days
Light off
2 days
Dash message, light on
1 week
Light off
1 day
Dash message, light on
replicated over the weeks and just drive with no attention to RPM

So changining the sensor did not cure it, but it changed the behaviour intially and now back to how it always was - it did something. So it cannot be the sensor. It always comes on when 5/6 miles into a journey if its been off. So maybe the heater wire in the sensor is not connected properly, I'm convinced its not mixture as I would 'feel' something.

Any clues, you see I'm trying to build a reason why, which might not be any real device fault and worthy of a garage pulling the car apart to find something which is not really faulty. Could supermarket petrol do this as I always use it ?

C
charlie8 is offline  
Status: now I'm not sure
AO Member
 
whatmoretyres's Avatar
 
Join Date: Mar 2007
Location: United Kingdom
County: Bucks
Posts: 989

Member car:

GT DIEsel

Re: Engine Warning Light Ambiguity

What grade of fuel are you using? Might be worth using super instead or changing brands?
whatmoretyres is offline  
jug
Status: -
AO Silver Member
 
jug's Avatar
 
Join Date: Jul 2007
Location: United Kingdom
County: Durham
Posts: 3,681
Re: Engine Warning Light Ambiguity

your situation does sound like the classic out of range lambda problem (try the redex trick to see). its a shame that so few dealerships hire mechancis who understand the difference between out of range and faulty. the lambda isnt the problem, its only the symptom, it is telling you there is a problem with your fueling. unfortunately the possible causes for unburnt fuel entering the exhaust are many, if the variator was stuck you could have scavenging, if the head gasket blew between 2 cylinders you get this fueling problem, even a coil with an intermittent fault, or a rusty earth strap resticting current flow leading to weak ignition, i've seen loads of different causes for the lambda to go out of range. it can also happen if you fit a universal lambda that has a different resistance to the oem lambda.
jug is offline  
Status: -
AO Member
 
charlie8's Avatar
 
Join Date: Jun 2005
Posts: 106

Member car:

GT JTS 2.0

Re: Engine Warning Light Ambiguity

Indeed, its driving me crazy. However as before no too concerned as it ALWAYS happens during the warm up and I don't feel anything. As its temp transition related the resistance thing or indeed connection thing I think is the reason. When they fiddled with the wires putting the new one in, it seemed to make it more intermittment, so I'm discounting mechanical issues on my evidence ( maybe foolishly )

All this started pretty soon after a cam belt change and follow up tappet cover gasket change due to oil leak due to cambelt change. Lots of tugging at the wires for that I'm sure ? Even got a rouge side light buld fail for one journey then went away after the jobs were done. I've never been one to pull working cars around so why I'm not droping it off for them to do surgery on.

C
charlie8 is offline  
(Post Link) post #22 of 32 Old 07-02-08 Thread Starter
Status: -
AO Member
 
Jsutton's Avatar
 
Join Date: May 2005
Location: Pembrokeshire
Posts: 265

Member car:

Alfa Romeo 147

Re: Engine Warning Light Ambiguity

I need some help.
I have just had two lambda probes replaced on my Alfa 147 T.S 1.6 (an Alfa garage diagnosed the problem for me). However, the light that was supposed to go away (the engine management light) has reappeared this morning.
There was a time delay between the last ECU system reset and the new lambda probes being fitted; i don't think the local garage that fitted the lambda probes reset the ECU, but only fitted the new lambdas. I was thinking that this error could have been registered during the time between the last ECU system reset and the lambda probes being fitted, but has only now prompted the engine management light. The Alfa Romeo garage assured me that the lambdas were the problem. Any ideas?

J.Sutton
Jsutton is offline  
jug
Status: -
AO Silver Member
 
jug's Avatar
 
Join Date: Jul 2007
Location: United Kingdom
County: Durham
Posts: 3,681
Re: Engine Warning Light Ambiguity

if your lambdas were the cause of the light then the light would switch off by itself when lambdas were replaced (can take a few journeys to switch off). that hasn't happened so your problem isnt solved. this sounds like another case of "out of range" lambda been mistaken for faulty lambda. "out of range" means your fueling is off, usually due to excessive overfueling, which can be caused by many things. the lambdas are only reporting that condition, not causing it. this is a very common mistake.
jug is offline  
(Post Link) post #24 of 32 Old 07-02-08 Thread Starter
Status: -
AO Member
 
Jsutton's Avatar
 
Join Date: May 2005
Location: Pembrokeshire
Posts: 265

Member car:

Alfa Romeo 147

Re: Engine Warning Light Ambiguity

I don't profess to know a lot about these kind of things but "my word these car diagnostic systems are useless! I suppose I'm going to have to get in touch with the Alfa garage again and explain the situation. Has this happened to anyone else? Those lambda probes cost just over 160!
Now I have to live with the prospect that the problem may not be solved
You know, Im just beginning to realise the truth behind the general consensus about the Alfa experience being a rollercoaster ride of emotion...
Do you guys have any advice?

Thanks
J.Sutton
Jsutton is offline  
Status: -
 
Join Date: Feb 2008
Posts: 11
Re: Engine Warning Light Ambiguity

Bosh O2 Sensors Are £80 Each From My Local Motor Factors....half Your £160.
PINFOLD0_2 is offline  
Reply

Go Back   Alfa Romeo Forum > Supported Alfa Romeo Models > Technical & Vehicle Assistance > Engines (TS, JTS, JTD & V6)

Tags
ambiguity , engine , light , warning

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

 
For the best viewing experience please update your browser to Google Chrome